Based on the site's "coming soon" slots, it seems that at first only the aforementioned 4 aces will be covered, but I suppose that if it gains traction more units could be added, as possibly indicated by the 2 empty slots further below. Eric Mansfield's, who also recently got a model kit for his MS-06R-1A, is one likely candidate, as is Shin Matsunaga (who now has model kits of both his original MS-06R-1 and a new distinctive MS-06R-1A from MSV-R).

Lastly, I also want to point out that Masaya's MS-06R-1A unit is mentioned to have 12 stars on its left arm. Official pictures of the gunplay of Uma's MS-06R-1A show it with 11 such stars on its arm as well, which makes me wonder if perhaps we will get more info on these aces' kill scores.